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### Course: Computer science theory>Unit 3

Lesson 1: Ancient information theory

# The battery and electromagnetism

The key technologies in our story. Created by Brit Cruise.

## Want to join the conversation?

• Why exactly do bubbles form on the outside of the zinc and copper wires? I understand why the flow of electrons happens, but how does this translate to bubbles?
• The process is called electrolysis, and it is a chemical reaction caused by a current. The bubbles are free ions, molecules with a negative charge.

Here is the Wikipedia snippet:

The main components required to achieve electrolysis are :
An electrolyte : a substance containing free ions which are the carriers of electric current in the electrolyte. If the ions are not mobile, as in a solid salt then electrolysis cannot occur.
A direct current (DC) supply : provides the energy necessary to create or discharge the ions in the electrolyte. Electric current is carried by electrons in the external circuit.
Two electrodes : an electrical conductor which provides the physical interface between the electrical circuit providing the energy and the electrolyte
• if you just put pennies together would it make a battery? because it has copper and zinc
• Yes! The only thing missing is an electrolyte (such as tap water, vinegar or even saliva!).
Here is a simple example I like to prove this to yourself.
- Find a (sanitized) piece of copper and zinc around the house:
- Touch them both to your tongue, but keep the metals separate.
- You will feel/taste nothing (except cold metal)
- Now while keeping the metals against your tongue, bring them together to they touch (so you have 3 points of contact, between the coins and on your tongue)
- Immediately you should taste an electric/acidic taste
- Separate the metals so they are not touching, the taste will stop!
• Would this work with today's pennies? He's referring to copper, but I thought that past a certain year they stopped using so much copper. Nowadays, there's less copper in a penny than there used to be.
• That's an interesting thought. Now days pennies are made out of zinc and then coated with copper. I'm guessing it would still work since the copper on the surface on the penny would still react with the solution but I'm not 100% on that.
• At what happens if you dissconect the two metals. will the bubbles on the copper pop?
• Yes they will stop (good question).
• Is this similar to the process by which water is turned into it's constituent components (i.e. O2, & H) for making rocket fuel? thanks T.S.
• Yes, water can be broken to its constituents oxygen and hydrogen by using electrolysis.
• Do motors have something to do with an electromagnet?
• So, they basically use copper and zinc in batteries? Then why are some batteries more expensive than others? :)
• Not all batteries use copper an zinc. Some (like the kind in laptops, phones, and other power-hungry devices) use lithium-ion and lithium-polymer metals. Pretty much any two metals and one acid can and have been used as batteries, although alkaline (zinc'n'manganese dioxide), LiPo (lithum-ion+polymer) and LIon (lithium metal and lithum ion) are the most common.
• Why does getting electrocuted result in muscle spasms during the electrocution? Why is electrocution represented by an X-Ray looking skeletons in cartoons?
• I have no idea about the X-ray, but muscle spasms could be caused by your nerves. Your ,muscles, in computer terms, are analog activated flexion actuators.
In English, this means that your muscles can be activated by electric current and the degree of flex and movement can be controlled by the amount of current.